Latest trial of a virus engineered to kill cancer shows promise

For roughly 20 years, scientists have been working to engineer a virus that will attack cancer. The basic idea is sound, and every few years there have been some promising-looking results, with tumors shrinking dramatically in response to an infection. But the viruses never seem to go beyond small trials, and the companies making them always seem to focus on different things. Recently, Nature Medicine described some further promising results, this time with a somewhat different approach to ensuring that the virus leads to the death of cancer cells: if the virus doesn’t kill the cells directly, it revs up the immune system to attack them. It’s not clear this result will make it to a clinic, but it provides a good opportunity to review the general approach of treating cancer with viruses. The basic idea is to leverage decades of work on some common viruses. This research has identified a variety...